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or 4 blade rotor heads. For example, setting phase trim to 90 degrees would
make full left aileron stick deflection tilt the swashplate fully forward. Note
that the phase angle will vary with rotor rpm and load so a “happy medium”
value must be sought when setting this value. See Section 11 of this user’s
manual for a step-by-step description of how to check the cyclic phasing.
Cyclic Servo Tab
The
Swash Servos
tab is found in the
Offline Setup Values
region of the main
SK720 setup software window as shown in Figure 19.4 below.
Figure 19.4 – SK720 Setup Software
Swash Servos
Tab
Servo Type:
Digital
uses higher frame rates than analog servos can handle
which, along with their better holding power, improves performance.
Do not
use digital frame rates for analog servos.
Linearize Swash Servos:
Compensates for non-linear blade pitch due to the arc
of the servo arm and the rotor.
Equalize Servo Speeds:
Accounts for the different radius of motion for the
servos in an eCCPM swashplate arrangement. For example, for a 120-degree
swash, an aggressive pitch motion will demand higher speed from the centre
servo than the left or right servos, so it may lag behind causing
uncommanded collective input. This feature slows all the servos evenly to
the maximum rate of the centre servo.
©2010 Skookum Robotics, Ltd
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Servo Speed:
Take this value from your servo manufacturer’s specifications.
Units are in seconds per 60 degrees of motion. This helps the gyro move the
swash evenly. This field only matters if
Equalize Servo Speeds
is on.
Servo Travel:
Scales the amount of motion each servo has on either side of
centre (endpoints). The servo travels can be set individually to trim the
swash to be level at max, zero and min collective pitch.
Servo Trims and Reversing:
Here each servo’s center point can be set and each
can be reversed if needed. This is the same idea as sub-trim on your
transmitter. Be careful that the servo doesn’t bind.
NOTE:
See Section 10, Step 4 for further information about how to use servo
travel, trims and reversing when setting up your helicopter.
Tail Servo Tab
The
Tail Servo
tab is found in the
Offline Setup Values
region of the main SK720
setup software window as shown in Figure 19.5 below.
Figure 19.5 – SK720 Setup Software
Tail Servo
Tab
By Name / Custom:
The tail servo type can be selected by either model number
and manufacturer, or if your servo type is not in the list, by its specifications.
Freq / Pulse:
If you have chosen to specify custom servo options, then you can
use this field to select the pulse-type and update rate (frequency). Note that
the wrong setting could cause the servo to bind and overheat! This field will
be greyed out if the
By Name
option is chosen.
